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Intel Lynnfield; Core i5 750 and Core i7 870 Evaluation




The launch of the new Lynnfield CPU and the P55 chipset from Intel has possibly been one of the worst product launches in Intel history. I am not saying the CPU is bad, in fact I would say just the opposite about the performance of the LGA-1156 CPUs.  However what has impacted the launch is that despite an NDA that did not lift until today, people have been buying both the Core i5 and Core i7 for LGA-1156 Socket in stores all over the world. Add to this a large influx of P55 motherboards that are on the shelves and you have a disastrous launch.  There is also the problem of the new naming convention. This little problem has been talked about at length and is, oddly enough, a large issue with many potential purchasers.

The problem as I hear it is with the Core i7 Lynnfield. You see for the most part when people think of Core i7 they will think LGA-1366 and X58. So the new Core i7 870 will seem to fall into that higher [and more expensive] category. However, while the naming is confusing, for us the performance differences were spot on and fit with the Intel marketing plan of putting the i7 870 as the high-end of the mainstream and dovetailing with the enthusiast level i7s.

In the pages below we will take a look at both the Core i5 and Core i7 Lynnfield CPUs. We will see how they perform at stock and what we can get from a quick overclock on air. Read on to see if this new CPU and chipset from Intel are worth your hard earned money.

What’s New
The biggest difference between Lynnfield and Nehalem [Core i7-900 series] is memory support. With Core i7 900 you get a full three channels but are limited to 1066 MHz for DDR3 support [at least that’s the official line, which we all know is the other BS, opposite of Bright Side]. Lynnfield cuts the channel support back to two and increases the official memory support to DDR3-1333. The removal of the Triple channel support does change the socket as the pin count drops from 1366 to 1156. Not having triple channel memory will hurt memory intensive applications like rendering and in some case high-level computations. This is not a signification issue as Lynnfield is not marketed for those high-end applications but more for mainstream gaming and work.

From there Lynnfield breaks down into a couple of sets; we have the current Flagship Core i7 and the mainstream Core i5. Although the Lynnfield Core i7 will only have dual channel support it will still carry the i7’s Hyper-Threading which allows two threads per core to run each CPU cycle.

Core i5 will lose Hyper-Threading but will maintain all of the other features found in the Core i7 870 although it will have a much slower clock speed. All three of the 1156 Lynnfields will have 8MB of L3 cache, an integrated memory controller, and a 95 Watt TDP.

Lynnfield is also smaller, and more power efficient than both the 1366 Core i7 and the previous Core 2 Quad generation. In fact comparing clock for clock the core i5 is roughly 20% faster than a Core 2 Quad [i5 750 Vs. Core 2 Quad Q9400]. But the size difference is also important; Intel has moved the graphics controls onto the CPU. This means that your PCIe graphics are executed on the CPU rather than in the MCP or Northbridge. It allows for an overall reduction of silicone by about 40% compared to the older Core 2 systems.

Both the Core i5 and Core i7 LGA-1156 CPUs are very impressive on paper, they take some of the best features of the Intel Nehalem architecture and put them into a low(er) cost package. This should shake up the AMD claim that they have the best performance/price point. But as we have not covered performance just yet we cannot say that for certain.

Test Systems and Comments

Our test systems are shown below:

Core i7 1366
Intel Core i7 920, 965 and 975
ASRock X58 Extreme (P130 BIOS)
6GB Kingston KHX12800D3T1K3/6GX
Zotac GeForce GTX 285 1GB
Kingston SSD Now M (Intel X25 SSD)
Cooler Master UCP 1100
Cooler Master Hyper 212 CPU cooler with extra fan
Windows 7 Ultimate x64 (RTM)

Lynnfield (LGA 1156) Core i5 and Core i7
Intel Core i7 870, Intel Core i5 750
ASRock P55 Deluxe (P130 BIOS)
4GB Kingston KHX12800D3T1K3/6GX
Zotac GeForce GTX 285 1GB
Kingston SSD Now M (Intel X25 SSD)
Cooler Master UCP 1100
Intel Supplied Cooler
Windows 7 Ultimate x64 (RTM)

AMD Phenom II X4 965
Asus M4A79T Deluxe
4GB Kingston KHX12800D3T1K3/6GX
Zotac GeForce GTX 285 1GB
Kingston SSD Now M (Intel X25 SSD)
Cooler Master UCP 1100
Cooler Master Hyper 212 CPU cooler with extra fan
Windows 7 Ultimate x64 (RTM)

The test systems represent a range of Intel Core i7 CPUs from the low to the two top end CPUs. The AMD Phenom II X4 955 BE is a comparably priced CPU to the Core i5. This is to see if AMD can keep the claim that they have the best price performance option.

When  AMD kicked out the Phenom IIs they hit a sweet spot for overclocking and tweaking. In some cases you could take a Phenom II and get a 1.5GHz+ OC without much effort at all. Intel on the other hand did not have the same type of luck with the Core i7. Yes you could get a pretty high OC but nowhere near what you could get with an AMD CPU. Well now Lynnfield is here and things have changed. With a very simple overclock we were able to get a 59% overclock. Using the simple overclocking tools in the ASRock P55 BIOS we were able to bump up the BClock to 202 and the Multiplier to 21. This gave us a 4231MHz Not bad at all temperatures were also more than acceptable. Bear in mind that this is overclocking using air cooling only, we did not had enough time to venture with more exotic cooling solutions such as liquid cooling or phase change.

The i7 870 was not as good on the simple air cooling I was using. For our 870 overclock we were able to reach 4029MHz. Temperatures were a little high but still well under the t-max for the CPU. When I attempted to push it further with the cooling I had I encountered stability problems.

I am sure that with more time and testing it would be possible to reach much higher clocks and we plan on finding out what those upper limits are for both the Core i5 and the AMD Phenom II.

CPUz for the Core i7 870

CPUz for the Core i5 750

For our performance testing we like to have a combination of synthetic and real-world testing.  For Synthetics we have the usual bank of tests from FutureMark, Maxon, Sisoft, and HyperPi.

These tests cover raw performance and potential; This side of testing brings out the basics of the CPU on its own while our real-world testing covers actual usage.

So for the numbers crowd; let’s get started with two of the industry standards for benchmarking system and gaming performance.

Futuremark’s PCMark Vantage
PCMark Vantage is a suite of tests designed to give an easily reproducible result. It is also often used for bragging rights.

In the case of Lynnfield, we find that the bragging rights go to Intel.

3DMark Vantage
3DMark Vantage is the second in the twin tests from FutureMark. This one turns to gaming. It is one of the first tests to use a complete DX10 pipeline for the rendering loops. We also see the first full-scale usage of PhysX in a gaming test.

Again Intel takes the top scores and when overclocked the Core i5 750 even beats the i7 975.

Sisoft Sandra
Next up we have Sisoft’s Sandra up on the board. Here we see the numbers that represent the raw potential of our CPUs.

In all of the tests in Sandra we see that the new Lynnfields hold their own very well and fall right into line with the market space they are aimed at. We also see the potential performance when overclocked.

Cinebench R10
This test from Maxon [the makers of Cinema 4D) covers CPU based rendering. The test renders a single file using a single CPU and then again using all the available CPUs.

In both Single and Multi-Core rendering the Intel CPUs take the prize. The Core i7 870 fall into 3rd place just behind the i7 965 while the Core i7 750 is in 4th. When overclocked this pair of CPUs takes the first and 2nd place fairly easily.

HyperPi 0.99
HyperPi is a great test to find out how well a CPU can handle large amounts of math based information. With HyperPi you have a single instance of SuperPi Mod 1.3 running on each logical and physical core. This puts a great deal of stress on the CPU and also on the internal memory controller.


Here our results surprise us. It seems that without the overhead of trying to push two full instances through each core the i5 can really crunch the numbers. This was unexpected, we had really thought that the lack of triple channel memory and hyperthreading would hurt the Core i5 but that was simply not the case.

Photoshop CS4
Photoshop is an industry standard image manipulation application. It is great for not only editing photographs but also for creating original content. For out testing here we used the Driverheavn Photoshop script. This is a custom built action that puts a stock image through a series of filters and allows you to record the time each takes to run.

I am sure you have figured out the deal here. Again the Lynnfield LGA 1156 CPUs do very well at stock speeds and simply great when overclocked.

Real World testing

LightWave 3D 9.6 x64
Our first real world test is LightWave 3D. This is an industry standard 3D Animation and rendering software from Newtek. For our testing runs we chose a sample scene from the Lighrtwave 8 content file that is installed with the new 9.6 version. Out tests were of the Moonbase scene frame 32. Settings were 1080 resolution, 7-Pass PLD, Gaussian Sharp reconstruction filter, and 512MB segment memory.

Now we really see the performance hit taken by the lack of the extra channel of memory. As it stands but the Core i7 870 and the Core i5 750 were very slow here. They still outperformed the AMD Phenom II X4 955. But even when overclocked could not compete with the 1366 i7s.

AutoGK is a compilation of transcoding applications wrapped up into a very nice installer and front end application. It is a great “one-stop” for transcoding or even re-encoding files. For our testing we transcode a 2-hour movie at 100% quality and record the time it takes to complete.

Again we see a performance hit from the loss of that extra memory channel. Only the i7 920 and the Phenom II performed worse than the two Lynnfield CPUs here. Granted they are still fast but you can see the difference. However, once overclocked they do manage to regain some of the speed.

Gaming is a very real-world test. We do not use benchmarking scripts but actually play the games though a pre-planned level and record the frame rates using FRAPS. This allows up to see exactly how the CPU benefits [or hinders] performance.

Cryostatis: Sleep of Reason
Cryostasis is an interesting game. It combines heavy physics into a horror/survival game into a sub-zero environment.  You also have to take “sprit journeys” to alter the past. If you change the past it affects your present. Settings used are shown below.

Gaming in Cryostasis shows us that the CPU does not have the large of an impact on gaming performance at high resolution. We do see the two top Core i7s take a healthy lead but for the i7 870 and i5 750 it is not going to give you that big of a boost over the competition.

FarCry 2
FarCry 2 is a large “sandbox” style game that does not have any real levels. It is all mission based but allows for a great deal of free movement in the environment. You take the role of a mercenary sent to kill “The Jackal” a dangerous gun runner. Unfortunately you are overcome by your malaria and end up serving as an errand boy for a local thug. Settings are show below:

Again we do not see much of a difference between the CPUs in terms of high resolution gaming performance.

A title from id Software Wolfenstein takes you back to World War II and the paranormal. The game has some interesting graphics and AI but unfortunately also has a frame rate cap at about 60 FP/s. Setting are shown below.

As you could have expected; not much to see here in terms of performance difference at high resolution.

Gaming recap
It has become more and more apparent that the CPU has little impact on high resolution gaming. Yes it can get you a couple of FPS more, but on the whole it is not going to affect frame rate so much. Where you see the difference is in AI, and other none graphical areas. It is not easily measureable and is often notes as a “more fluid” game experience. Unfortunately there is nothing that can measure that yet.

According to Intel the Core i7 870 will sell for $560 while the Core i5 750 will go for $196. This puts the Core i7 in the upper end of the mainstream and matches its performance as well. For the Core i5 we see Intel meeting AMD on the playing field swinging. They now have a CPU that can meet AMD pricewise and beat them performance wise at that same price point. This is not good for AMD’s marketing strategy. In the recent past they have maintained that the Phenom II can outperform a similarly priced Intel CPU. With the Core i5 things have changed.

Lynnfield is an impressive architecture. It serves to reduce the cost of Nehalem technology in both dollars and power. At the same time Intel has upped the performance bar for the mainstream. They have entered this market at two very important places; entry level pricing and high-performance [for the mainstream] and while there will be CPUs in-between the Core i5 750 and the i7 870 will be the most popular.

Intel has also struck back at AMD on the overclocking field. The Core i7 1366 CPUs were not very overclocking friendly with the average person and without the air of super cooling only the 920 was going to give you great clocks. Again Lynnfield changes that; the Core i5 750 was easily overclocked to 4.2 GHz completely stable. We are certain that with a little more time and tweaking we can get more out of it as well. So the playing field is changing rapidly AMD looks set to lose its most important marketing advantage over Intel and Core i5 and i7 1156 CPUs will gain good market share. They are impressive in many ways and perform very well even without triple-channel memory. I hope that AMD has an answer to this out in the near future; otherwise it looks like it will be a very “blue” 3rd and 4th quarter for AMD.

Original Author: Sean Kalinich

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